Process of making vanillin



Patented Apr. 30, 1946 UNITED STATES PATENT OFFICE PROCESS OF MAKING VANILLIN Richard Servio, Brooklyn, N. Y., assignor to Marathon Corporation, a corporation of Wisconsin No Drawing. Application August 6, 1943. Serial No. 497,689

12 Claims. (Cl. 260-600) This invention relates to a process of making cium compounds, both soluble and insoluble, and vanillin and isolating vanillin in the form oi very large amounts of organic matter mainly in alkali vanillate from alkaline solutions. More the form of soluble lignin sulphonate salts. This particularly the invention relates to the recovery, vanillin-containing liquor is extracted by counconcentration and purification of alkali vanillate, tor-current flow with approximately 2,000 gallons such as sodium or potassium vanillate, from an or butyl alcohol to 1,000 gallons of the vanillinalkaline aqueous solution, especially when the 50- containing liquor at about 73 C. The vanillin lution contains large amounts of organic matter which may amount to around 7.5 s. p. 1., exists havin solubilities diilerent from alkali vanillate. n he anillin-contalning solution as a sodium United States Patent No. 2,104,701, January 4, i0 vanillate and the counter-current extraction 1938, issued to Sandborn discloses a process of transfers this vanillin compound as such from making vanillin by heat-treating an alkaline the strongly alkaline aqueous solution of high aqueous solution or lignin substance, preferably N820 and or anic matter oncentrations into the in the form of lignin sulphonic acid compounds, b tyl alcohol. (hereinafter referred to as bu yl to convert lignin into a soluble vanillin compound, 15 alcohol extract). such as sodium vanillate, separating such vanillin The butyl alcohol extract thus obtained ancompound from the alkaline aqueous solution by aly s approximately 17 E- P- of total lids counter-current extraction with a suitable wamade up roug y of 1.8 an 1. or NazO, 4.0 g. p. l.

tor-immiscible solvent, such as normal butyl alo a l in d e ala ce lar l r anic mat- 001101, and recovering the solvent for reuse and 20 In y improv d process t is butyl alcohol the vanillin constituent for further purification extract containing sodium vanillate is eluted by by any known means, such as by distilling the counter-current flow with approximately 1,000 solvent as its water-binary to leave the vanillin allons of'water to which around 2.5 p. l. of compoundv in an alkaline aqueous solutio for NaOH has been added for 4,000 gallons of the further refining. 5 butyl alcohol extract at around 70 C. I have As a new and commercially useful improvefound that the presence or addition of a conment of such distillati r dur I h i trolled small amount of NaOH or its equivalent covered that the non-aqueous solvent, for ex-' to the elution water is necessary to facilitate the ample, butyl alcohol, can be recovered in pracremoval of the sodium vanillate from the butyl tically vanillin-iree condition suitable for reuse 81601101 extract by Pr i g the formation of in the process without distillation or further purtoo stable emulsions in the elution extractors.

ification n t vanmin compound can be The dilute caustic soda solution also tends to statained in aqueous solution favorable for further bilize the i m vahilletee presence of at purification by a counter-current elution or exas 29 E- D- 1- and n Over 10 P- 1- f N OH traction or the vanillin-containing organic 501- as n e extraction water is e ed necess ry for vent with a, ontroll d m unt of wat preferpractical elution of the sodium vanillate, but the ably containing a. ll am unt of u ti soda, presence of too much caustic soda impairs the ef- My method h th advantage of economizmg in fieiency of the elution since NaOH tends to lower the use of steam and also avoids the loss of vanilhe sol bility of sodium vanillate in water. KOH lin by heating that occurs in straight distillation 40 y be u ed in place of NaOH if desired. Readof the butyl alcoh extract. ily ionizable alkalhmetal salts, such for example The iollowing procedures and conditions for as potassium or so i m h r de, sodium sulp commercial operation or my improved process will 1' i m car on e may be used in place of serve to illustrate the invention, but I do not in- NaOH i ut t e same amounts to p eve tend t limit it scope t u pecified conditions forming stable emulsions, but these salts are less except as defined in. the appended claims. desirable since they lower the solubility of the In accordance with the method disclosed in sodium vanillate in water to a er ex ent than Patent No. 2,104,701 an alkaline aqueous liquor NaOH. Caustic soda also lowers the solubility of containing vanillin is obtained by cooking ligni sodium vanlllate in water but to a lesser degree sulphonic compounds under pressure with water th n s l and caustic alk li, h as di hydroxide, The spent butyl alcohol extract after the elu- This liquor (hereinafter designated as vaniilintion m y analyze around 10 ep. 1. of total solids containing liquor) may contain around 400 of which 0.5 s. P. 1. is NazO, 0.4 g. p. l. is vanillin gram per liter (g. p. l.) of total solids. When and the balance is largely organic matter. This the lignin-containing substances are pressure spent butyl alcohol is reused in the process to cooked with sodium hydroxide the resulting liquor extract more vanillin-containing liquor.

contains sodium vanillate. free caustic soda The vaniilin-containing alkaline water as it (NaOH) and various sodium salts, both organic exits from the elution extractors may analyze and inorganic. in amounts equivalent to about around 25 g. p. l. of total solids of which about 78 g. p. l. of NaaO, considerable amounts 01' cal- 00 8.0 g. p. l. is No.30, 10.0 s. p. l. is vanillin and the balance is organic matter. The resulting aqueoussolution contains substantially all the sodium, vaniilate content of the original butyl alcohol extract in an alkaline aqueous solution oi lesser volume, lower content in organic matter impurities and higher concentration of vanillin compound. This solution may be processed by any suitable conversion and purification procedures to yield vanillin of high purity.

Having described my invention, what I claim is:

1. The process of removing sodium vanillate from its alkaline solution in butyl alcohol which comprises eluting said organic solvent with a weak aqueous solution containing 2 to 10 grams perliterorcausticalkalitoyieldanalkaline aqueous solution containing substantially all the said vanillin salt and practically vanillin-tree butyl alcohol suitable for reuse. I

2. The process of removing sodium vanillate from its alkaline solution in butyl alcohol which comprises elutlng said organic solvent with a weak aqueous solution containing 2 to 10 grams per liter oi a readily ionisable alkali-metal salt to yield an alkaline aqueous solution containing substantially all the said vanillin salt and practically vanillin-free butyl alcohol suitable for reuse.

3. The process removing sodium vanillate from a solution of sodium vanillate in butyl alcohol which comprises eluting said solution with an aqueous solution containing 2 to 10 grams per liter 01 sodium chloride to yield an aqueous solution containing substantially all the sodium vanillate in said butyl alcohol solution.

4. The process of removing sodium vanillate from a solution of sodium vanillate in butyl alcohol which comprises eluting a volume of said solution with a weak aqueous solution containing 2 to 10 grams per liter of caustic soda and 0! less volume than said solution oi butyl alcohol to yield an aqueous solution containing substantially all the sodium vanillate in said butyl alcohol solution. 1

5. The process of removing sodium vanillate from a solution of sodium vaniliate in butyl alcohol which comprises eluting a volume oi said solution with a weak aqueous solution containing 2 to 10 gramsper liter of caustic soda and of about one-fourth the volume 0! said solution of butylalcohol to yield an aqueous solution containing substantially all the sodium vanillate in'said butyl alcohol solution.

6. In the process of making vanillin by making lignin-containing substances under pressure with water and caustic alkali to form an alkaline liquor containing a soluble alkali-metal salt of vanillin, soluble organic compounds and other impurities, the steps of extracting said vanillin salt from said alkaline liquor with butyl alcohol to produce an alkaline solution of said vanillin salt in butyl alcohol and eluting said butyl alcohol solution with a weak aqueous solution containing 2 to 10 grams per liter of caustic alkali to yield an alkaline aqueous solution containing substantially all 01 the said vanillin salt and a practically vanillin-free butyl alcohol for reuse.

7. In the process of making vanillin by making lignin-containing substances under pressure with water and caustic soda to form an alkalin liquor containing a sodium vanillate, soluble organic compounds and other impurities, the steps of extracting said vanillin salt from said alkaline liquor with butyl alcohol to produce an alkaline solution of said vanillin salt in butyl alcohol and eluting said butyl alcohol solution with a week asaaeo':

aqueous solution containing 2 to 10 grams per liter of caustic alkali to yield an alkaline aqueous solution con substantially all oi the said vanillin salt and a practically vanillin-tree butyl alcohol for reuse.

8. Intheprocessoimakingvsnillinbycookins iignln-eontaining substances under pressure with water and sodium hydroxide to form an alkaline liquor containing sodium vanillate, soluble organic compounds and other impurities, the steps of extracting the sodium vanillate from said liqnor with butyl alcohol to produce a solution of sodium vanilla-te in butyl alcohol, eluting said solution with a weak aqueous solution containing atlesst2andnotmorethanl0gramsper liter of caustic soda, to yield an aqueous solution containing substantially all the sodium vanillate insaid butyl alcohol solution.

9. In the process oi making vanillin by cooking lignin-containing substances under pressure with water and sodium hydroxide to form an alkaline liquor containing sodium vanillate soluble organic compounds and other impurities. the steps of extracting the sodium vanillate irom said liquor with butyl alcohol to produce a solution 0! sodium vanillate in butyl alcohol, eluting said solution with a weak aqueous solution containing 2 to 10 grams per liter oi caustic soda and of less volume than said solution of butyl alcohol to yield an aqueous solution containing substantially all the sodium vanillate in saidbutyl alcohol solution.

10. In the process of making vanillin by cooking lignin-containing substances under pressure with water and sodium hydroxide to form an alkaline liquor containing sodium vaniliate, soluble organic compounds and other impurities. the steps of extracting the sodium vaniiiate from said liquor with butyl alcohol to produce a solution of sodium vanillate in butyl alcohol, elutins said solution containing 2 to 10 grams per liter with a weak aqueous solution of caustic soda to yield an aqueous solution containing substantially all the sodium vaniilate in said butyl alcohol solution, and recovering vanillin from said aqueous solution.

11. In the process or making vanillin by cooking lignin-containing substances under pressure with water and sodium hydroxide to form an alkaline liquor containing sodium vanillate, soluble organic compounds and other impurities, the steps of extracting the sodium vanillate irom said liquor with butyl alcohol to produce a solution of sodium vanillate in butyl alcohol, eiutingsaid solution with a weak aqueous solution containing 2 to 10 grams per liter of caustic soda to yield an aqueous solution containing substantially all the sodium vanillaie in said butyl alcohol solution, recovering sodium vaniilate from said aqueous solution and purifying the vanillin.

12. In the process of making vanillin by cooking lignin-containing substances under pressure with water and sodium hydroxide to form an alkaline liquor containing sodium vanillate, soluble organic compounds and other impurities, the steps of extracting the sodium vanillate from said liquor with butyl alcohol to produce a solution of sodium vanillate in butyl alcohol, eluting said solution with a weak aqueous solution containing 2 to 10 grams per liter of caustic soda to yield an aqueous solution containing substantially all the sodium vanillate present in the said butyl alcohol solution and practically vanillin-tree butyl alcohol, and reusing said butyl alcohol for extracting sodium vanillate from freshly cooked liquor.

RICHARD SERVIB.

Certificate of Correction Patent No. 2,399,607. April 30, 1946.

RICHARD SERVIS It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 41, claim 10, strike out the words containing 2 to 10 grams per liter and insert the same after solution in line 42, same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 30th day of July, A. D. 1946.

[smut] LESLIE FRAZER, a

First Assistant Commissioner of Patents. 

